/*
 * Event loop based on Windows events and WaitForMultipleObjects
 * Copyright (c) 2002-2006, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"
#include <winsock2.h>

#include "common.h"
#include "eloop.h"


struct eloop_sock {
        int sock;
        void *eloop_data;
        void *user_data;
        eloop_sock_handler handler;
        WSAEVENT event;
};

struct eloop_event {
        void *eloop_data;
        void *user_data;
        eloop_event_handler handler;
        HANDLE event;
};

struct eloop_timeout {
        struct os_time time;
        void *eloop_data;
        void *user_data;
        eloop_timeout_handler handler;
        struct eloop_timeout *next;
};

struct eloop_signal {
        int sig;
        void *user_data;
        eloop_signal_handler handler;
        int signaled;
};

struct eloop_data {
        void *user_data;

        int max_sock;
        size_t reader_count;
        struct eloop_sock *readers;

        size_t event_count;
        struct eloop_event *events;

        struct eloop_timeout *timeout;

        int signal_count;
        struct eloop_signal *signals;
        int signaled;
        int pending_terminate;

        int terminate;
        int reader_table_changed;

        struct eloop_signal term_signal;
        HANDLE term_event;

        HANDLE *handles;
        size_t num_handles;
};

static struct eloop_data eloop;


int eloop_init(void *user_data)
{
        os_memset(&eloop, 0, sizeof(eloop));
        eloop.user_data = user_data;
        eloop.num_handles = 1;
        eloop.handles = os_malloc(eloop.num_handles *
                                  sizeof(eloop.handles[0]));
        if (eloop.handles == NULL)
                return -1;

        eloop.term_event = CreateEvent(NULL, FALSE, FALSE, NULL);
        if (eloop.term_event == NULL) {
                printf("CreateEvent() failed: %d\n",
                       (int) GetLastError());
                os_free(eloop.handles);
                return -1;
        }

        return 0;
}


static int eloop_prepare_handles(void)
{
        HANDLE *n;

        if (eloop.num_handles > eloop.reader_count + eloop.event_count + 8)
                return 0;
        n = os_realloc(eloop.handles,
                       eloop.num_handles * 2 * sizeof(eloop.handles[0]));
        if (n == NULL)
                return -1;
        eloop.handles = n;
        eloop.num_handles *= 2;
        return 0;
}


int eloop_register_read_sock(int sock, eloop_sock_handler handler,
                             void *eloop_data, void *user_data)
{
        WSAEVENT event;
        struct eloop_sock *tmp;

        if (eloop_prepare_handles())
                return -1;

        event = WSACreateEvent();
        if (event == WSA_INVALID_EVENT) {
                printf("WSACreateEvent() failed: %d\n", WSAGetLastError());
                return -1;
        }

        if (WSAEventSelect(sock, event, FD_READ)) {
                printf("WSAEventSelect() failed: %d\n", WSAGetLastError());
                WSACloseEvent(event);
                return -1;
        }
        tmp = os_realloc(eloop.readers,
                         (eloop.reader_count + 1) * sizeof(struct eloop_sock));
        if (tmp == NULL) {
                WSAEventSelect(sock, event, 0);
                WSACloseEvent(event);
                return -1;
        }

        tmp[eloop.reader_count].sock = sock;
        tmp[eloop.reader_count].eloop_data = eloop_data;
        tmp[eloop.reader_count].user_data = user_data;
        tmp[eloop.reader_count].handler = handler;
        tmp[eloop.reader_count].event = event;
        eloop.reader_count++;
        eloop.readers = tmp;
        if (sock > eloop.max_sock)
                eloop.max_sock = sock;
        eloop.reader_table_changed = 1;

        return 0;
}


void eloop_unregister_read_sock(int sock)
{
        size_t i;

        if (eloop.readers == NULL || eloop.reader_count == 0)
                return;

        for (i = 0; i < eloop.reader_count; i++) {
                if (eloop.readers[i].sock == sock)
                        break;
        }
        if (i == eloop.reader_count)
                return;

        WSAEventSelect(eloop.readers[i].sock, eloop.readers[i].event, 0);
        WSACloseEvent(eloop.readers[i].event);

        if (i != eloop.reader_count - 1) {
                os_memmove(&eloop.readers[i], &eloop.readers[i + 1],
                           (eloop.reader_count - i - 1) *
                           sizeof(struct eloop_sock));
        }
        eloop.reader_count--;
        eloop.reader_table_changed = 1;
}


int eloop_register_event(void *event, size_t event_size,
                         eloop_event_handler handler,
                         void *eloop_data, void *user_data)
{
        struct eloop_event *tmp;
        HANDLE h = event;

        if (event_size != sizeof(HANDLE) || h == INVALID_HANDLE_VALUE)
                return -1;

        if (eloop_prepare_handles())
                return -1;

        tmp = os_realloc(eloop.events,
                         (eloop.event_count + 1) * sizeof(struct eloop_event));
        if (tmp == NULL)
                return -1;

        tmp[eloop.event_count].eloop_data = eloop_data;
        tmp[eloop.event_count].user_data = user_data;
        tmp[eloop.event_count].handler = handler;
        tmp[eloop.event_count].event = h;
        eloop.event_count++;
        eloop.events = tmp;

        return 0;
}


void eloop_unregister_event(void *event, size_t event_size)
{
        size_t i;
        HANDLE h = event;

        if (eloop.events == NULL || eloop.event_count == 0 ||
            event_size != sizeof(HANDLE))
                return;

        for (i = 0; i < eloop.event_count; i++) {
                if (eloop.events[i].event == h)
                        break;
        }
        if (i == eloop.event_count)
                return;

        if (i != eloop.event_count - 1) {
                os_memmove(&eloop.events[i], &eloop.events[i + 1],
                           (eloop.event_count - i - 1) *
                           sizeof(struct eloop_event));
        }
        eloop.event_count--;
}


int eloop_register_timeout(unsigned int secs, unsigned int usecs,
                           eloop_timeout_handler handler,
                           void *eloop_data, void *user_data)
{
        struct eloop_timeout *timeout, *tmp, *prev;

        timeout = os_malloc(sizeof(*timeout));
        if (timeout == NULL)
                return -1;
        os_get_time(&timeout->time);
        timeout->time.sec += secs;
        timeout->time.usec += usecs;
        while (timeout->time.usec >= 1000000) {
                timeout->time.sec++;
                timeout->time.usec -= 1000000;
        }
        timeout->eloop_data = eloop_data;
        timeout->user_data = user_data;
        timeout->handler = handler;
        timeout->next = NULL;

        if (eloop.timeout == NULL) {
                eloop.timeout = timeout;
                return 0;
        }

        prev = NULL;
        tmp = eloop.timeout;
        while (tmp != NULL) {
                if (os_time_before(&timeout->time, &tmp->time))
                        break;
                prev = tmp;
                tmp = tmp->next;
        }

        if (prev == NULL) {
                timeout->next = eloop.timeout;
                eloop.timeout = timeout;
        } else {
                timeout->next = prev->next;
                prev->next = timeout;
        }

        return 0;
}


int eloop_cancel_timeout(eloop_timeout_handler handler,
                         void *eloop_data, void *user_data)
{
        struct eloop_timeout *timeout, *prev, *next;
        int removed = 0;

        prev = NULL;
        timeout = eloop.timeout;
        while (timeout != NULL) {
                next = timeout->next;

                if (timeout->handler == handler &&
                    (timeout->eloop_data == eloop_data ||
                     eloop_data == ELOOP_ALL_CTX) &&
                    (timeout->user_data == user_data ||
                     user_data == ELOOP_ALL_CTX)) {
                        if (prev == NULL)
                                eloop.timeout = next;
                        else
                                prev->next = next;
                        os_free(timeout);
                        removed++;
                } else
                        prev = timeout;

                timeout = next;
        }

        return removed;
}


int eloop_is_timeout_registered(eloop_timeout_handler handler,
                                void *eloop_data, void *user_data)
{
        struct eloop_timeout *tmp;

        tmp = eloop.timeout;
        while (tmp != NULL) {
                if (tmp->handler == handler &&
                    tmp->eloop_data == eloop_data &&
                    tmp->user_data == user_data)
                        return 1;

                tmp = tmp->next;
        }

        return 0;
}


/* TODO: replace with suitable signal handler */
#if 0
static void eloop_handle_signal(int sig)
{
        int i;

        eloop.signaled++;
        for (i = 0; i < eloop.signal_count; i++) {
                if (eloop.signals[i].sig == sig) {
                        eloop.signals[i].signaled++;
                        break;
                }
        }
}
#endif


static void eloop_process_pending_signals(void)
{
        int i;

        if (eloop.signaled == 0)
                return;
        eloop.signaled = 0;

        if (eloop.pending_terminate) {
                eloop.pending_terminate = 0;
        }

        for (i = 0; i < eloop.signal_count; i++) {
                if (eloop.signals[i].signaled) {
                        eloop.signals[i].signaled = 0;
                        eloop.signals[i].handler(eloop.signals[i].sig,
                                                 eloop.user_data,
                                                 eloop.signals[i].user_data);
                }
        }

        if (eloop.term_signal.signaled) {
                eloop.term_signal.signaled = 0;
                eloop.term_signal.handler(eloop.term_signal.sig,
                                          eloop.user_data,
                                          eloop.term_signal.user_data);
        }
}


int eloop_register_signal(int sig, eloop_signal_handler handler,
                          void *user_data)
{
        struct eloop_signal *tmp;

        tmp = os_realloc(eloop.signals,
                         (eloop.signal_count + 1) *
                         sizeof(struct eloop_signal));
        if (tmp == NULL)
                return -1;

        tmp[eloop.signal_count].sig = sig;
        tmp[eloop.signal_count].user_data = user_data;
        tmp[eloop.signal_count].handler = handler;
        tmp[eloop.signal_count].signaled = 0;
        eloop.signal_count++;
        eloop.signals = tmp;

        /* TODO: register signal handler */

        return 0;
}


#ifndef _WIN32_WCE
static BOOL eloop_handle_console_ctrl(DWORD type)
{
        switch (type) {
        case CTRL_C_EVENT:
        case CTRL_BREAK_EVENT:
                eloop.signaled++;
                eloop.term_signal.signaled++;
                SetEvent(eloop.term_event);
                return TRUE;
        default:
                return FALSE;
        }
}
#endif /* _WIN32_WCE */


int eloop_register_signal_terminate(eloop_signal_handler handler,
                                    void *user_data)
{
#ifndef _WIN32_WCE
        if (SetConsoleCtrlHandler((PHANDLER_ROUTINE) eloop_handle_console_ctrl,
                                  TRUE) == 0) {
                printf("SetConsoleCtrlHandler() failed: %d\n",
                       (int) GetLastError());
                return -1;
        }
#endif /* _WIN32_WCE */

        eloop.term_signal.handler = handler;
        eloop.term_signal.user_data = user_data;
                
        return 0;
}


int eloop_register_signal_reconfig(eloop_signal_handler handler,
                                   void *user_data)
{
        /* TODO */
        return 0;
}


void eloop_run(void)
{
        struct os_time tv, now;
        DWORD count, ret, timeout, err;
        size_t i;

        while (!eloop.terminate &&
               (eloop.timeout || eloop.reader_count > 0 ||
                eloop.event_count > 0)) {
                tv.sec = tv.usec = 0;
                if (eloop.timeout) {
                        os_get_time(&now);
                        if (os_time_before(&now, &eloop.timeout->time))
                                os_time_sub(&eloop.timeout->time, &now, &tv);
                }

                count = 0;
                for (i = 0; i < eloop.event_count; i++)
                        eloop.handles[count++] = eloop.events[i].event;

                for (i = 0; i < eloop.reader_count; i++)
                        eloop.handles[count++] = eloop.readers[i].event;

                if (eloop.term_event)
                        eloop.handles[count++] = eloop.term_event;

                if (eloop.timeout)
                        timeout = tv.sec * 1000 + tv.usec / 1000;
                else
                        timeout = INFINITE;

                if (count > MAXIMUM_WAIT_OBJECTS) {
                        printf("WaitForMultipleObjects: Too many events: "
                               "%d > %d (ignoring extra events)\n",
                               (int) count, MAXIMUM_WAIT_OBJECTS);
                        count = MAXIMUM_WAIT_OBJECTS;
                }
#ifdef _WIN32_WCE
                ret = WaitForMultipleObjects(count, eloop.handles, FALSE,
                                             timeout);
#else /* _WIN32_WCE */
                ret = WaitForMultipleObjectsEx(count, eloop.handles, FALSE,
                                               timeout, TRUE);
#endif /* _WIN32_WCE */
                err = GetLastError();

                eloop_process_pending_signals();

                /* check if some registered timeouts have occurred */
                if (eloop.timeout) {
                        struct eloop_timeout *tmp;

                        os_get_time(&now);
                        if (!os_time_before(&now, &eloop.timeout->time)) {
                                tmp = eloop.timeout;
                                eloop.timeout = eloop.timeout->next;
                                tmp->handler(tmp->eloop_data,
                                             tmp->user_data);
                                os_free(tmp);
                        }

                }

                if (ret == WAIT_FAILED) {
                        printf("WaitForMultipleObjects(count=%d) failed: %d\n",
                               (int) count, (int) err);
                        os_sleep(1, 0);
                        continue;
                }

#ifndef _WIN32_WCE
                if (ret == WAIT_IO_COMPLETION)
                        continue;
#endif /* _WIN32_WCE */

                if (ret == WAIT_TIMEOUT)
                        continue;

                while (ret >= WAIT_OBJECT_0 &&
                       ret < WAIT_OBJECT_0 + eloop.event_count) {
                        eloop.events[ret].handler(
                                eloop.events[ret].eloop_data,
                                eloop.events[ret].user_data);
                        ret = WaitForMultipleObjects(eloop.event_count,
                                                     eloop.handles, FALSE, 0);
                }

                eloop.reader_table_changed = 0;
                for (i = 0; i < eloop.reader_count; i++) {
                        WSANETWORKEVENTS events;
                        if (WSAEnumNetworkEvents(eloop.readers[i].sock,
                                                 eloop.readers[i].event,
                                                 &events) == 0 &&
                            (events.lNetworkEvents & FD_READ)) {
                                eloop.readers[i].handler(
                                        eloop.readers[i].sock,
                                        eloop.readers[i].eloop_data,
                                        eloop.readers[i].user_data);
                                if (eloop.reader_table_changed)
                                        break;
                        }
                }
        }
}


void eloop_terminate(void)
{
        eloop.terminate = 1;
        SetEvent(eloop.term_event);
}


void eloop_destroy(void)
{
        struct eloop_timeout *timeout, *prev;

        timeout = eloop.timeout;
        while (timeout != NULL) {
                prev = timeout;
                timeout = timeout->next;
                os_free(prev);
        }
        os_free(eloop.readers);
        os_free(eloop.signals);
        if (eloop.term_event)
                CloseHandle(eloop.term_event);
        os_free(eloop.handles);
        eloop.handles = NULL;
        os_free(eloop.events);
        eloop.events = NULL;
}


int eloop_terminated(void)
{
        return eloop.terminate;
}


void eloop_wait_for_read_sock(int sock)
{
        WSAEVENT event;

        event = WSACreateEvent();
        if (event == WSA_INVALID_EVENT) {
                printf("WSACreateEvent() failed: %d\n", WSAGetLastError());
                return;
        }

        if (WSAEventSelect(sock, event, FD_READ)) {
                printf("WSAEventSelect() failed: %d\n", WSAGetLastError());
                WSACloseEvent(event);
                return ;
        }

        WaitForSingleObject(event, INFINITE);
        WSAEventSelect(sock, event, 0);
        WSACloseEvent(event);
}


void * eloop_get_user_data(void)
{
        return eloop.user_data;
}
